Project Summary We are requesting funds to purchase a cluster of instruments from the TSE PhenoMaster indirect calorimetry system that controls, acquires, and analyzes metabolic parameters and laboratory environmental conditions. The system is equipped with special gas sensors to measure hydrogen (H2), hydrogen sulfide (H2S), volatile organic compounds, and the relative abundance of 13CO2/12CO2. It includes modules to accommodate mouse- or rat-sized cages with HEPA-filtered and autoclavable parts for germ-free/gnotobiotic applications in an environmental chamber that controls illumination, humidity, and temperature. The system includes 4 treadmills to assess exercise capacity as well as a module to separate, quantify, and freeze feces and urine for further analyses. These instruments will prompt the formation of the Small Animal Metabolic Phenotyping Facility (SAMPF) at the University of Wisconsin-Madison to provide access to a range of modalities for metabolic phenotyping. Importantly, the SAMPF has been assigned space in a centrally located vivarium with an instrument room, a diet-preparation room, a cage-washing room, a surgery suite, and 7 individual animal housing rooms to enable users from anywhere on and off the UW campus to use the instruments. We have observed increased demand for metabolic phenotyping of genetically engineered mice and rats with diverse experimental needs, which cannot be satisfied by the mouse indirect calorimetry systems currently available on campus. In response to this need, we have partnered with the Morgridge Institute for Research, UW-Madison School of Medicine and Public Health, Department of Nutritional Sciences, Department of Biochemistry, and the Office of the Vice Chancellor for Research and Graduate Education and identified matching financial support for this application. Committed funds will support the purchase of complementing instruments, dedicated SAMPF personnel, and an extended 5-year service contract. This cluster of instruments will be the first of its kind on the UW-Madison campus and will fill a critical gap in available technologies to UW investigators. It will immediately serve more than twenty research laboratories, most of which are currently funded by the NIH, with wide-ranging expertise from mitochondria biology and aging to exocytosis and neurological diseases. Overall, success of this application will greatly strengthen current NIH-funded projects and allow our users to explore new lines of research not approachable previously in the absence of this new platform. It will be a keystone addition to the research capabilities on our campus and in our nation, and it will synergistically enhance NIH- funded research to further improve the health for populations in the US and beyond.